Dual-mode endoscope catheter and imaging system

Abstract

The invention discloses a dual-mode endoscope catheter and an imaging system.The endoscope catheter comprises an imaging optical fiber bundle, an imaging lens set focused on the end face of one side of the imaging optical fiber bundle and a protective sleeve arranged on the peripheral side of the imaging optical fiber bundle in a sleeving mode, and the imaging optical fiber bundle comprises confocal optical fibers and a wide-field imaging catheter; the wide-field imaging conduit comprises a wide-field illumination optical fiber and a wide-field imaging optical fiber which are coaxially arranged, one end of the protective sleeve is connected with an end cap, the imaging lens group is located in the end cap, the imaging lens group comprises a wide-field imaging group and a confocal imaging group, the working distance of the wide-field imaging group is millimeter-scale, and the working distance of the confocal imaging group is micron-scale. The whole endoscope catheter can realize two imaging modes of wide-field imaging and confocal imaging by adjusting the working distance of the imaging lens group. The wide-field imaging mode is large in visual field range, confocal imaging navigation can be achieved, the confocal imaging mode is small in working distance, and tissue cell level images can be obtained for auxiliary diagnosis and treatment.

Description

Technical Field

[0001] The present invention belongs to the field of endoscopes, and more specifically, relates to a dual-mode endoscope catheter and an imaging system. Background Art

[0002] Bile duct stricture is caused by benign stricture or malignant tumor. The causes of benign bile duct stricture are diverse, such as bile duct injury, inflammatory changes of the bile duct, or scarring and constriction of the bile duct lumen after biliary surgery. Malignant bile duct stricture is mainly caused by tumor compression. At present, when treating benign and malignant bile duct strictures, the local tissue is hard, making it difficult for conventional dilating probes to pass through, which is inconvenient for subsequent operations. At the same time, biliary stricture is one of the common diseases in clinical practice. The judgment of its benign and malignant nature is very important for the choice of treatment methods and the prognosis of patients, but clinical differential diagnosis is very difficult, especially for malignant biliary stricture. Therefore, accurate early diagnosis of biliary stricture is very important.

[0003] At present, the pathological histological examination methods for bile duct stricture diseases mainly include cell brushing under ERCP, bile drainage cytology examination, biopsy forceps examination, etc. The preoperative diagnosis rate of malignant bile duct stricture by the above methods is still low and the examination procedures are complicated. At present, there is a confocal microscope probe dedicated to ERCP. The microscope probe is directly placed at the bile duct stricture or other suspicious lesions, and observed as perpendicular to the mucosal surface as possible. The microscope probe is connected to a laser scanner and a confocal processor, and can provide real-time in-vivo microscopic images of the tissue structure and function on the mucosal surface and a certain depth (40 - 70 μm) under the mucosa of the bile duct wall, including epithelial cells, vascular density, and dynamic blood flow, etc., so as to detect neoplastic new blood vessels and immediately judge the nature of the bile duct stricture, which cannot be achieved in in-vitro tissue cytology examination.

[0004] In the actual application process, the confocal microscope probe has the following deficiencies: 1. Confocal examination needs to rely on a large-field examination device for guidance to enter the examination site and cannot be used independently; 2. At the same time, at present, due to the diameter limitation of the confocal microscope probe, the field of view is too small, less than 1 mm; 3. The choledochoscope cannot enter the stricture site and needs to enter for examination with the help of a catheter with a small lens. The choledochoscope has a large size, and the minimum outer diameter of the head end currently used in clinical practice is also 3.2 mm. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the present invention provides a dual-mode endoscope catheter and an imaging system, aiming to solve the problems of small field of view in confocal examination and difficult examination in narrow spaces.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided a dual-mode endoscope catheter, which includes an imaging fiber bundle, an imaging lens group that is focused on one end face of the imaging fiber bundle, and a protective sleeve sleeved on the periphery of the imaging fiber bundle. The imaging fiber bundle includes a confocal fiber and a wide-field imaging catheter. The wide-field imaging catheter includes a wide-field illumination fiber and a wide-field imaging fiber that are coaxially arranged. One end of the protective sleeve is connected with an end cap, and the imaging lens group is located in the end cap. The imaging lens group includes a wide-field imaging group and a confocal imaging group. The working distance of the wide-field imaging group is on the order of millimeters, and the working distance of the confocal imaging group is on the order of micrometers.

[0007] Through the above technical solution, the wide-field imaging catheter and the confocal fiber are integrated together in the protective sleeve, and an imaging lens group with two working distances is arranged in the end cap. Moreover, the image planes at the two working distances coincide on one end face of the confocal fiber and the wide-field imaging catheter close to the end cap, so that the entire endoscope catheter can achieve two imaging modes: wide-field imaging and confocal imaging, and the two imaging modes can be realized by adjusting the working distance of the imaging lens group. In the wide-field imaging mode, the field of view is large, and a macroscopic image can be obtained for confocal imaging navigation and positioning. In the confocal imaging mode, the working distance is small, and a tissue cell-level image can be obtained for auxiliary diagnosis and treatment.

[0008] Further, the cross-section of the end cap is elliptical, and the confocal fiber and the wide-field imaging catheter are arranged side by side. Or, the cross-section of the end cap is circular, and the confocal fiber and the wide-field imaging catheter are coaxially arranged, and the confocal fiber is located in the inner layer of the wide-field imaging catheter.

[0009] Further, each lens in the imaging lens group includes a wide-field imaging area and a confocal imaging area. The wide-field imaging areas of all lenses form the wide-field imaging group, and the confocal imaging areas of all lenses form the confocal imaging group. The central thicknesses of the wide-field imaging area and the confocal imaging area of a single lens are not equal.

[0010] The present invention also provides a dual-mode endoscope imaging system. The imaging system includes a wide-field imaging mode and a confocal imaging mode, and includes

[0011] A light source module: including a confocal imaging light source, a wide-field imaging light source, a first beam combiner, and an expander lens group. The confocal imaging light source and the wide-field imaging light source are respectively located on two incident light paths of the first beam combiner, and the expander lens group is located on the outgoing light path of the first beam combiner;

[0012] Scanning module: sequentially includes a two-dimensional scanning device, a coupling objective lens, and an endoscope catheter as described in claim 3. The two-dimensional scanning device is used to deflect the confocal imaging light. The coupling objective lens is used to couple the imaging signal into the endoscope catheter. The endoscope catheter is used to focus the confocal imaging light source or the wide-field imaging light source at the target position to excite a confocal signal light or a wide-field signal light. The two-dimensional scanning device is located on the outgoing light path of the beam expander group. A relay lens group and a scatter plate that can cut into / cut out the light path are sequentially arranged between the two-dimensional scanning device and the coupling objective lens;

[0013] Confocal detection module: includes a dichroic mirror for separating the confocal signal light and a first detection component for collecting the confocal signal light. The dichroic mirror is located between the beam expander group and the two-dimensional scanning device. The beam expander group is located on the incident light path of the dichroic mirror. The two-dimensional scanning device is located on the outgoing light path of the dichroic mirror. The first detection component is located on the transmitted light path of the dichroic mirror;

[0014] Wide-field detection module: includes a polarization filter for separating the wide-field signal light and a second detection component for collecting the wide-field signal light. The polarization filter is synchronized with the scatter plate to cut into / cut out the light path. When the polarization filter cuts into the light path, the relay lens group is located on the incident light path of the polarization filter, the scatter plate is located on the transmitted light path of the polarization filter, and the second detection component is located on the reflected light path of the polarization filter.

[0015] Furthermore, the specific usage method of the wide-field imaging mode is as follows:

[0016] The polarization filter and the scatter plate cut into the light path. The confocal imaging light source is turned off. The wide-field imaging light source emits the illumination light required for wide-field imaging. After passing through the first beam combiner by transmission and then being expanded by the beam expander group, the expanded light beam enters the stationary two-dimensional scanning device after being reflected by the dichroic mirror, and then is reflected to the relay lens group. Then, it passes through the polarization filter and the scatter plate in sequence and enters the coupling objective lens, and is coupled into the imaging optical fiber bundle of the endoscope catheter. Then, it is focused on the object side through the wide-field imaging area of the imaging lens group in the end cap, and the target is imaged in the wide-field imaging mode. The generated wide-field signal light returns along the original light path to the polarization filter, and is detected and imaged by the second detection component after being reflected by the polarization filter.

[0017] Furthermore, the specific usage method of the confocal imaging mode is as follows:

[0018] The polarization filter and the scatter sheet cut off the optical path. The wide-field imaging light source is turned off, and the confocal imaging light source emits the excitation light required for confocal imaging. After being transmitted by the first beam combiner and then expanded by the beam expander group, the expanded beam is reflected by the dichroic mirror and enters the two-dimensional scanning device in the deflection and scanning motion state, and thus is deflected into the relay lens group. Then, the beams deflected at various angles enter the coupling objective lens and are coupled into the imaging optical fiber bundle of the endoscope catheter. Then, it is focused on the object side through the confocal imaging area of the imaging lens group in the end cap, and the target is imaged in the confocal mode, exciting the confocal signal light. The confocal signal light returns along the original optical path to the dichroic mirror and is detected and imaged by the first detection component after being transmitted by the dichroic mirror.

[0019] Through the above technical solution, the imaging system of the present invention can switch between the wide-field imaging mode and the confocal imaging mode. The former obtains a large field of view and macroscopic images, providing navigation and guidance for the latter, enabling the latter to reach specific parts and obtain tissue cell-level images. This dual-mode endoscope imaging system combines the advantages of wide-field imaging and confocal imaging, greatly enriching the application scenarios of confocal imaging.

[0020] Further, the coupling objective lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from the two-dimensional scanning device to the endoscope catheter direction, and the third lens is a doublet lens.

[0021] Further, the surface of the coupling objective lens facing the two-dimensional scanning device is the object surface, and the surface facing the endoscope catheter is the image surface. The clear aperture radius of the surface of the first lens close to the image surface is R12, the clear aperture radius of the surface of the second lens close to the object surface is R21, and the clear aperture radius of the surface of the second lens close to the image surface is R22. The clear aperture radius of the surface of the third lens close to the object surface is R31, and the clear aperture radius of the surface of the third lens close to the image surface is R33. The clear aperture radius of the surface of the fourth lens close to the object surface is R41, and the clear aperture radius of the surface of the fourth lens close to the image surface is R42.

[0022] Further, the surface of the coupling objective lens facing the scatter sheet is the object surface, and the surface facing the endoscope catheter is the image surface. The radius of curvature of the surface of the first lens close to the object surface is r11, and the radius of curvature of the surface of the first lens close to the image surface is r12. The radius of curvature of the surface of the second lens close to the object surface is r21, and the radius of curvature of the surface of the second lens close to the image surface is r22. The focal length of the first lens is f1, and the focal length of the second lens is f2, satisfying:

[0023] Further, the focal length of the coupling objective lens is 9 mm, the parfocal distance is 45 mm, and the maximum clear aperture radius is 8 mm.

[0024] Generally speaking, compared with the prior art, the above technical solution conceived by the present invention can achieve the following beneficial effects:

[0025] (1) Solve the problems of small field of view and inspection guidance in confocal imaging. The confocal imaging and wide-field imaging are designed together. By moving the imaging lens group to adjust the working distance, two-mode imaging and switching are realized, which is convenient to reach the specified part during confocal imaging to obtain cell-level images, greatly enriching the application scenarios of confocal endoscope imaging.

[0026] (2) The confocal optical fiber and the wide-field imaging catheter are integrated together to achieve miniaturized design, which is beneficial to improving the problems of too small channel caused by bile duct stenosis and difficult to pass through large-scale cooperation, as well as the problem of relying on external equipment to guide and assist in inspection.

[0027] (3) A combined sleeve matching the endoscope catheter is designed, which can not only protect the endoscope catheter, but also solve the problems of passing through a narrow space and performing confocal inspection in a narrow space when examining patients with biliary stenosis. The pre-dilation treatment or the mode of synchronously advancing the combined sleeve and the endoscope catheter can be used first.

[0028] (4) An objective lens coupled with the imaging optical fiber bundle in the endoscope catheter is proposed, which can not only match the imaging optical fiber bundle to achieve flat field and achromatism, but also achieve telecentricity, thus significantly improving the coupling efficiency with the imaging optical fiber bundle and reducing crosstalk. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the overall structure of the endoscope catheter;

[0030] Figure 2 In (a), it is a schematic diagram of the end structure of the endoscope catheter when the cross-section of the end cap is circular;

[0031] Figure 2 In (b), it is a schematic diagram of the end structure of the endoscope catheter when the cross-section of the end cap is elliptical;

[0032] Figure 3 is a schematic diagram of the optical path transmission of the imaging lens group when the cross-section of the end cap is circular;

[0033] Figure 4 is a schematic diagram of the overall structure of the combined sleeve;

[0034] Figure 5 is a schematic diagram of the overall structure when the endoscope catheter and the combined sleeve are used in combination;

[0035] Figure 6 is a schematic diagram of the cross-section of the end cap in some embodiments;

[0036] Figure 7 Schematic cross - sectional view of the end cap in some other embodiments;

[0037] Figure 8 Schematic structural view of the lenses in the imaging lens group when the cross - section of the end cap is circular;

[0038] Figure 9 Schematic diagram of the optical path transmission of the endoscope imaging system;

[0039] Figure 10 Schematic structural view of the coupling objective lens optical path in some embodiments;

[0040] Figure 11 is Figure 10 Schematic diagram of the chief ray angles of different fields of view in the optical path of

[0041] Figure 12 Schematic structural view of the coupling objective lens optical path in some other embodiments;

[0042] Figure 13 is Figure 12 Schematic diagram of the chief ray angles of different fields of view in the optical path of

[0043] In the figure, 11 is the confocal optical fiber; 12 is the confocal microscopy probe; 13 is the wide - field imaging catheter, 131 is the wide - field imaging optical fiber, 132 is the wide - field illumination optical fiber; 14 is the protective sleeve; 15 is the end cap; 16 is the imaging lens group, 161 is the wide - field imaging area, 162 is the confocal imaging area; 171 is the head end, 172 is the dilation balloon, 173 is the catheter main body, 174 is the catheter handle, 175 is the working channel, 176 is the operation port; 21 is the confocal imaging light source, 22 is the wide - field imaging light source, 23 is the first beam combiner, 24 is the beam expander group; 31 is the two - dimensional scanning device, 32 is the relay lens group, 33 is the diffuser, 34 is the coupling objective lens, 35 is the imaging fiber bundle; 41 is the dichroic mirror, 42 is the first detection component, 421 is the pinhole lens, 422 is the pinhole, 423 is the fluorescence detector; 51 is the polarization filter, 52 is the second detection component; L1 is the first lens, L2 is the second lens, L3 is the third lens, L4 is the fourth lens, L5 is the fifth lens. Detailed implementation manners

[0044] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] As Figure 1 , Figure 2 andFigure 3 As shown in the figure, the present invention provides a dual-mode endoscope catheter, which includes an imaging fiber bundle 35, an imaging lens group 16 that is focused on one end face of the imaging fiber bundle 35, and a protective sleeve 14 sleeved on the periphery of the imaging fiber bundle 35. The imaging fiber bundle 35 includes a confocal fiber 11 and a wide-field imaging catheter 13. The wide-field imaging catheter 13 includes a wide-field illumination fiber 132 and a wide-field imaging fiber 131 arranged coaxially. One end of the protective sleeve 14 is connected with an end cap 15, and the imaging lens group 16 is located inside the end cap 15. The imaging lens group 16 includes a wide-field imaging group and a confocal imaging group. The working distance of the wide-field imaging group is in the order of millimeters, and the working distance of the confocal imaging group is in the order of micrometers.

[0046] Specifically, the confocal fiber 11 of the present application can directly adopt an existing confocal microscopy probe 12. The core component of the confocal microscopy probe 12 is the confocal fiber 11. In the endoscope catheter of the present application, the confocal microscopy probe 12 is taken, and only the confocal fiber 11 is improved. The wide-field imaging catheter 13 and the confocal fiber 11 are integrated into an imaging fiber bundle 35 and arranged inside the protective sleeve 14. An end cap 15 is arranged at the end of the protective sleeve 14, and an imaging lens group 16 is arranged inside. The imaging lens group 16 has two working distances: when using the wide-field imaging group for imaging, the working distance is at the millimeter level, and the imaging field of view is larger, which can observe the macroscopic image of the object side and navigate for confocal imaging; after the wide-field imaging navigation and positioning, the working distance of the imaging lens group 16 can be adjusted to the order of micrometers, which is convenient for confocal imaging through the confocal imaging group. One end face of the confocal fiber 11, the wide-field illumination fiber 132, and the wide-field imaging fiber 131 close to the end cap 15 is kept flush by grinding, and this end face is the image plane of the wide-field imaging group and the confocal imaging group. In both imaging modes, the imaging lens group 16 images on the flush end face of the confocal fiber 11 and the wide-field imaging catheter 13, and then the optical path is transmitted through the confocal fiber 11 and the wide-field imaging catheter 13, which is convenient for subsequent image detection and processing.

[0047] During ERCP surgery, a confocal microscopy probe 12 is needed for the diagnosis and treatment of biliary and pancreatic duct diseases. However, confocal examination needs to rely on a large-field inspection device for guidance to enter the inspection site and cannot be used independently because the confocal field of view is too small, less than 1 mm. The dual-mode endoscope catheter of the present invention combines the confocal imaging group and the large-field wide-field imaging group, so that the technical solution of the present invention not only has the function of confocal imaging but also has the function of a large-field inspection device, solving the problems of the small field of view and inspection guidance of the confocal catheter.

[0048] Further, as Figure 4 and Figure 5As shown, it further includes a combined cannula, the combined cannula includes a head end 171, an expansion balloon 172, a cannula body 173, and a cannula handle 174 connected in sequence. A working channel 175 and an operation port 176 are further provided inside the combined cannula. The protective cannula 14 is disposed inside the combined cannula through the working channel 175.

[0049] Specifically, the head end 171 has a trapezoidal smooth structure to prevent damage to the tissue mucosa during the pushing process. The combined cannula is in an overall "Y" shape. The protective cannula 14 provided with the confocal optical fiber 11 and the wide-field imaging catheter 13 penetrates into the combined cannula through the working channel. The combined cannula has the functions of guiding, protecting, expanding, and cleaning the field of view. When examining a patient with biliary stricture, the stenosis site can be expanded through the expansion balloon 172 to ensure the smooth passage of the aforementioned endoscopic catheter. The port of the working channel 175 is located on the cannula handle 174, and various instruments (such as the aforementioned endoscopic catheter or an existing confocal microscopy probe 12) can penetrate through this port; the operation port 176 is used for pressure input when the expansion balloon 172 expands. In addition, the operation port 176 can also be set as a dual port to meet the injection function other than pressurization or the insertion function of other devices adapted to the needs (such as the insertion of a guide wire).

[0050] The aforementioned endoscopic catheter of the present invention can be used in combination with the combined cannula, or can be used without the combined cannula. For example, when used in combination with the combined cannula, the guide wire can be first inserted into the designated position along the narrow part, and then the combined cannula is pushed along the direction of the guide wire. When the combined cannula encounters a narrow part and cannot enter, the expansion balloon 172 is used for expansion.

[0051] Specifically, as Figure 6 shown, in some embodiments, the cross-section of the end cap 15 is oval, and the confocal optical fiber 11 and the wide-field imaging catheter 13 are arranged side by side. Figure 1 The confocal optical fiber 11 and the wide-field imaging catheter 13 shown in [figure number] are arranged side by side. This solution is more conducive to the layout and optical design of the internal lens at the end of the end cap 15, and the imaging implementation method is relatively simple. For example, the confocal imaging group and the wide-field imaging group can be directly arranged side by side in the end cap 15, and the confocal imaging group is matched with the confocal optical fiber 11, and the wide-field imaging group is matched with the wide-field imaging catheter 13. Both the confocal imaging group and the wide-field imaging group can adopt existing lens combinations, and they can be installed side by side in the end cap 15 to achieve the optical design. The lens combinations of the wide-field imaging and confocal imaging groups are not expanded here.

[0052] As Figure 7As shown, in some other embodiments, the cross-section of the end cap 15 is circular, the confocal optical fiber 11 and the wide-field imaging catheter 13 are coaxially arranged, and the confocal optical fiber 11 is located inside the wide-field imaging catheter 13. Inside the wide-field imaging catheter 13, the wide-field imaging optical fiber 131 is located inside the wide-field illumination optical fiber 132. At this time, the confocal optical fiber 11, the wide-field imaging optical fiber 131, and the wide-field illumination optical fiber 132 are coaxially arranged from the inside to the outside, located in the inner layer, the middle layer, and the outer layer respectively, and the whole structure is more compact. However, since the confocal optical fiber 11 and the wide-field imaging catheter 13 are coaxial, the wide-field imaging group and the confocal imaging group cannot be arranged side by side as in the previous embodiments.

[0053] Specifically, as Figure 3 and Figure 8 shown, when the confocal optical fiber 11 and the wide-field imaging catheter 13 are coaxial, each lens in the imaging lens group 16 includes a wide-field imaging area 161 and a confocal imaging area 162. The wide-field imaging areas 161 of all the lenses form the wide-field imaging group, and the confocal imaging areas 162 of all the lenses form the confocal imaging group. The central thicknesses of the wide-field imaging area 161 and the confocal imaging area 162 of a single lens are not equal.

[0054] By designing the functions of two regions for each lens, the wide-field imaging group and the confocal imaging group are integrated into a lens combination. After the light passes through the wide-field imaging areas 161 of each lens in sequence, it is focused on the object side with a working distance WDw in millimeters; after the light passes through the confocal imaging areas 162 of each lens in sequence, it is focused on the object side with a working distance WDc in micrometers, so as to meet the image transmission requirements when the wide-field imaging optical fiber 131 and the confocal optical fiber 11 are coaxial. The partition design of the lens can be realized by customized grinding and processing.

[0055] The present invention also proposes a dual-mode endoscope imaging system, as Figure 9 shown, including

[0056] Light source module: providing confocal imaging light or wide-field imaging light;

[0057] Scanning module: sequentially including a two-dimensional scanning device 31, a coupling objective lens 34, and an endoscope catheter as described in any one of claims 1-5. The two-dimensional scanning device 31 is used to deflect the confocal imaging light, the coupling objective lens 34 is used to couple the confocal imaging light or the wide-field imaging light into the endoscope catheter, and the endoscope catheter is used to focus the confocal imaging light or the wide-field imaging light on the target position to excite confocal signal light or wide-field signal light;

[0058] Confocal detection module: It includes a dichroic mirror 41 for separating the confocal signal light and a first detection component 42 for collecting the confocal signal light;

[0059] Wide-field detection module: It includes a polarization filter 51 for separating the wide-field signal light and a second detection component 52 for collecting the wide-field signal light.

[0060] The imaging system of the present invention can switch between the wide-field imaging mode and the confocal imaging mode. The former obtains a large field of view and macroscopic images, providing navigation and guidance for the latter, enabling the latter to reach specific parts and obtain tissue cell-level images. This dual-mode endoscope imaging system combines the advantages of wide-field imaging and confocal imaging, greatly enriching the application scenarios of confocal imaging.

[0061] In the imaging system of the present invention, all optical elements except the endoscope catheter can be integrated into the confocal main unit. In addition to the confocal optical fiber 11 on the existing confocal microscopy probe 12, there is also a probe connector. In the endoscope catheter, the confocal optical fiber 11, the wide-field illumination optical fiber 132, and the wide-field imaging optical fiber 131 are integrated to form an imaging optical fiber bundle 35. Therefore, the existing connection method can be used to directly connect and focus with the coupling objective lens 34 of the confocal main unit through the probe connector on the confocal microscopy probe 12. In this setting method, only the optical elements required for wide-field imaging need to be added to the existing confocal main unit, and the wide-field illumination optical fiber 132, the wide-field imaging optical fiber 131, and the protective sleeve 14 are added to the confocal optical fiber 11 of the existing confocal microscopy probe 12, with the least improvement to the existing confocal microscopy imaging system.

[0062] Specifically, the light source module includes a confocal imaging light source 21, a wide-field imaging light source 22, a first beam combiner 23, and an expander lens group 24. The confocal imaging light source 21 and the wide-field imaging light source 22 are respectively located on two incident light paths of the first beam combiner 23, and the expander lens group 24 is located on the output light path of the first beam combiner 23.

[0063] The two-dimensional scanning device 31 in the scanning module is located on the output light path of the expander lens group 24. A relay lens group 32 and a scatter plate 33 that can be cut into / cut out of the light path are sequentially arranged between the two-dimensional scanning device 31 and the coupling objective lens 34.

[0064] The confocal detection module includes a dichroic mirror 41 located between the expander lens group 24 and the two-dimensional scanning device 31. The expander lens group 24 is located on the incident light path of the dichroic mirror 41, the two-dimensional scanning device 31 is located on the output light path of the dichroic mirror 41, and the first detection component 42 is located on the transmitted light path of the dichroic mirror 41.

[0065] The wide-field detection module includes a polarization filter 51 that synchronously cuts into / cuts out of the optical path with the scattering sheet 33. When the polarization filter 51 cuts into the optical path, the relay lens group 32 is located on the incident optical path of the polarization filter 51, the scattering sheet 33 is located on the transmitted optical path of the polarization filter 51, and the second detection component 52 is located on the reflected optical path of the polarization filter 51.

[0066] The imaging system of the present invention includes a confocal imaging mode and a wide-field imaging mode. In the wide-field imaging mode, the polarization filter 51 and the scattering sheet 33 cut into the optical path, the confocal imaging light source 21 is turned off, and the wide-field imaging light source 22 emits the illumination light required for wide-field imaging. After being transmitted through the first beam combiner 23 and then expanded by the beam expander group 24, the expanded light beam is reflected by the dichroic mirror 41 and enters the two-dimensional scanning device 31 in a stationary state. Subsequently, it is reflected to the relay lens group 32, and then passes through the polarization filter 51 and the scattering sheet 33 in sequence and enters the coupling objective lens 34, and is coupled into the imaging optical fiber bundle 35 of the endoscope catheter. Then, it is focused on the object side through the wide-field imaging area 161 of the imaging lens group 16 in the end cap 15, and the target is imaged in the wide-field imaging mode. The generated wide-field signal light returns along the original optical path to the polarization filter 51, and after being reflected by the polarization filter 51, it is detected and imaged by the second detection component 52. Because the working distance of the wide-field imaging group is relatively large, a macroscopic image with a large field of view range can be obtained, which is convenient for navigation and positioning for confocal imaging.

[0067] In the confocal imaging mode, the polarization filter 51 and the scattering sheet 33 cut out of the optical path, the wide-field imaging light source 22 is turned off, and the confocal imaging light source 21 emits the excitation light required for confocal imaging. After being transmitted through the first beam combiner 23 and then expanded by the beam expander group 24, the expanded light beam is reflected by the dichroic mirror 41 and enters the two-dimensional scanning device 31 in a deflected and scanned state, so as to be deflected into the relay lens group 32. Then, the light beams at various deflected angles enter the coupling objective lens 34, and are coupled into the imaging optical fiber bundle 35 of the endoscope catheter. Then, it is focused on the object side through the confocal imaging area 162 of the imaging lens group 16 in the end cap 15, and the target is imaged in the confocal mode, exciting the confocal signal light. The confocal signal light returns along the original optical path to the dichroic mirror 41, and after being transmitted through the dichroic mirror 41, it is detected and imaged by the first detection component 42. Because the working distance of the confocal imaging group is relatively small, an image at the tissue cell level with a small field of view range and high detail can be obtained.

[0068] Specifically, the confocal imaging light source 21 can be a laser, such as a 488nm laser. The dichroic mirror 41 is used to separate the confocal signal light for confocal imaging during detection and imaging. The two-dimensional scanning device 31 can be a two-dimensional scanning galvanometer. The relay lens group 32 is used to extend the optical path and can be two symmetric doublet lenses.

[0069] Specifically, the wide-field imaging light source 22 includes an illumination light source, a wide-field light source, and a second beam combiner. The illumination light source and the wide-field light source are respectively located on two incident light paths of the second beam combiner, and the first beam combiner 23 is located on the exit light path of the second beam combiner. During wide-field imaging, the light emitted by the illumination light source and the wide-field light source is combined by the second beam combiner and then reflected by the first beam combiner 23 to the dichroic mirror 41. The wide-field light source should cover as wide a wavelength range as possible and should not cover the wavelength range of the confocal imaging light source 21. The light emitted by the wide-field light source is polarized light with a specific polarization state, such as P polarization. The polarization filter 51 is used to transmit the wide-field imaging light source 22 with a polarization state and reflect the non-polarized wide-field signal light from the coupling objective lens 34. The polarization filter 51 has an optical polarization film.

[0070] The full width at half maximum angle of the transmittance of the bidirectional scattering distribution function of the scattering sheet 33 is θ FWHM , f 44 represents the focal length of the coupling objective lens 34, and d 35 represents the imaging circle diameter of the imaging fiber bundle 35. θ FWHM is large enough so that the coupling objective lens 34 can obtain a large enough angular field of view to cover the fiber end face of the wide-field imaging catheter 13 near the coupling objective lens 34 in the imaging fiber bundle 35.

[0071] Specifically, the first detection component 42 can be a pinhole 422, a lens 421, a pinhole 422, and a fluorescence detector 423 sequentially arranged on the transmitted light path of the dichroic mirror 41. The pinhole 422 lens 421 is used to focus the confocal signal light, and the pinhole 422 is used for spatial filtering to filter the confocal signal light at non-target lateral positions and non-target depths to achieve confocal imaging. The fluorescence detector 423 is used to convert the confocal signal light into an electrical signal. The second detection component 52 can be a tube lens and a camera sequentially arranged on the reflected light path of the polarization filter 51. The first detection component 42 and the second detection component 52 can adopt other confocal imaging and wide-field imaging component parts in the prior art.

[0072] Such as Figure 10 shown, specifically, the coupling objective lens includes a first lens L1, a second lens L2, a third lens L3L, a fourth lens L4, and a fifth lens L5 sequentially arranged from the two-dimensional scanning device to the endoscope catheter direction. The third lens L3 is a doublet lens.

[0073] The focal length of the coupled objective lens is 9 mm. The designed wavelengths of the objective lens are 0.488 μm, 0.515 μm, and 0.55 μm. These three wavelengths are selected as typical wavelengths for fluorescence imaging. If the design of the objective lens meets the imaging requirements at these three typical wavelengths, it can meet the requirements of fluorescence imaging. The parfocal distance is 45 mm, which can be consistent with the product rules of most commercially available microscope objective lens brands, such as those of companies like Zeiss, Leica, and Olympus, facilitating replacement and comparative testing. The maximum semi-aperture is 8 mm, which can leave sufficient redundancy for the design of structural components, enabling the final outer diameter of the finished product to be the same as that of most manufacturers, thus facilitating replacement and comparative testing with objective lenses of other manufacturers. The numerical aperture of the objective lens is 0.4. In the scenario of biomedical imaging endoscopes, the numerical aperture of the imaging fiber bundle used is usually 0.4. If the numerical aperture of the objective lens is also 0.4, crosstalk between the cores can be minimized to the greatest extent.

[0074] The first lens L1 is used to bend the incident light beam. The second lens L2 further bends and begins to converge the light beam inward. At this time, the first lens L1 and the second lens L2 correct aberrations such as coma, astigmatism, and field curvature, leaving a small amount of chromatic aberration and accumulating a large positive spherical aberration. The third lens L3 further converges the light beam, not only further correcting coma, astigmatism, and field curvature but also providing a large negative spherical aberration. This can compensate for the spherical aberration accumulated by the first lens L1 and the second lens L2. The fourth lens L4 focuses the light beam and can almost completely correct various aberrations remaining in the left lenses. The fifth lens L5 focuses the light beam and corrects various aberrations remaining in all the left lenses. Or, during the coupling process, the fifth lens L5 protects the end face of the imaging fiber bundle in the subsequent optical path and blocks scattered light in the left optical path. Through the cooperation between the lenses, not only can the imaging fiber bundle be matched to achieve a flat field and achromatism, but telecentricity is also achieved, thus significantly improving the coupling efficiency with the imaging fiber bundle and reducing crosstalk.

[0075] One side of the coupled objective lens facing the two-dimensional scanning device is the object surface, and the side facing the endoscope catheter is the image surface.

[0076] In some embodiments, as Figure 10 shown, the third lens L3 is a doublet lens. Both sides of the first lens L1 bulge towards the image surface. One side of the second lens L2 close to the object surface bulges towards the object surface, and the side close to the image surface bulges towards the image surface. One side of the third lens L3 close to the object surface bulges towards the object surface, the middle cemented surface bulges towards the object surface, and the side close to the image surface bulges towards the image surface. Both sides of the fourth lens L4 bulge towards the object surface, and both sides of the fifth lens L5 bulge towards the object surface.

[0077] The radius of curvature of one side of the fifth lens L5 close to the object surface is r51, the clear aperture semi-diameter is R51, the radius of curvature of the side close to the image surface is r52, the clear aperture semi-diameter is R52, and the central thickness is d5, satisfying: 4.803。

[0078] The clear aperture radius of the surface of the first lens L1 close to the image plane is R12, the clear aperture radius of the surface of the second lens L2 close to the object plane is R21, and the clear aperture radius of the surface of the second lens L2 close to the image plane is R22. The clear aperture radius of the surface of the third lens L3 close to the object plane is R31, and the clear aperture radius of the surface of the third lens L3 close to the image plane is R33. The clear aperture radius of the surface of the fourth lens L4 close to the object plane is R41, and the clear aperture radius of the surface of the fourth lens L4 close to the image plane is R42. The clear aperture radius of the surface of the fifth lens L5 close to the object plane is R51.

[0079] The radius of curvature of the surface of the first lens L1 close to the object plane is -8.388 mm, and the clear aperture radius is 4.97 mm. The radius of curvature of the surface of the first lens L1 close to the image plane is -23.282 mm, and the clear aperture radius is 7.03 mm. The material of the first lens L1 is H-ZLAF78B, and the central thickness is 5.284 mm. The central thickness between the adjacent surfaces of the first lens L1 and the second lens L2 is 0.500 mm.

[0080] The radius of curvature of the surface of the second lens L2 close to the object plane is 142.532 mm, and the clear aperture radius is 7.67 mm. The radius of curvature of the surface of the second lens L2 close to the image plane is -21.856 mm, and the clear aperture radius is 8.65 mm. The material of the second lens L2 is H-ZF71GT, and the central thickness is 7.000 mm. The central thickness between the adjacent surfaces of the second lens L2 and the third lens L3 is 1.413 mm.

[0081] The radius of curvature of the surface of the third lens L3 close to the object plane is 43.906 mm, and the clear aperture radius is 8.63 mm. The radius of curvature of the cemented surface in the middle is 12.006 mm, and the clear aperture radius is 7.77 mm. The radius of curvature of the surface of the third lens L3 close to the image plane is -41.515 mm, and the clear aperture radius is 7.93 mm. The third lens L3 is composed of two lenses cemented together. The material of the lens close to the object plane is H-ZF73, and the central thickness is 7.000 mm. The material of the lens close to the image plane is H-ZPK5, and the central thickness is 5.616 mm. The central thickness between the adjacent surfaces of the third lens L3 and the fourth lens L4 is 0.500 mm.

[0082] The radius of curvature of the surface of the fourth lens L4 close to the object plane is 12.261 mm, and the clear aperture radius is 7.88 mm. The radius of curvature of the surface of the fourth lens L4 close to the image plane is 192.304 mm, and the clear aperture radius is 7.37 mm. The material of the fourth lens L4 is H-FK55, and the central thickness is 4.036 mm. The central thickness between the adjacent surfaces of the fourth lens L4 and the fifth lens L5 is 0.500 mm.

[0083] The radius of curvature of one side of the fifth lens L5 close to the object surface is 10.620 mm, the clear aperture radius is 6.46 mm, the radius of curvature of the other side close to the image surface is 6.935 mm, and the clear aperture radius is 3.16 mm. The material of the fifth lens L5 is H-ZLAF89L, the central thickness is 7.000 mm, and the central thickness between the side of the fifth lens L5 close to the image surface and the end face of the imaging fiber bundle is 4.522 mm.

[0084] The focal lengths of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are: -17.31 mm, 23.44 mm, 158.66 mm, 23.47 mm, -313.23 mm respectively. The total optical length TTL of the entire objective lens is 45 mm.

[0085] r51 = 10.620 mm, R51 = 6.46 mm, r52 = 6.935 mm, R52 = 3.16 mm, d5 = 7.000 mm, R12 = 7.03 mm, R21 = 7.67 mm, R22 = 8.65 mm, R31 = 8.63 mm, R33 = 7.93 mm, R41 = 7.88 mm, R42 = 7.37 mm,

[0087] Figure 11 The chief ray angles of different fields of view are shown. It can be seen from the figure that the chief ray angles within the entire field of view are all less than 0.12°, indicating good telecentric characteristics. In this way, the chief rays of different fields of view are not only almost parallel to the axes of the respective cores, but also have almost the same fiber incident cone angles, which can maximize the coupling efficiency between the coupling objective lens and the imaging fiber bundle.

[0088] In some other embodiments, as Figure 12 shown, both sides of the first lens L1 bulge towards the image surface, one side of the second lens L2 close to the object surface bulges towards the object surface and the other side close to the image surface bulges towards the image surface, one side of the third lens L3 close to the object surface bulges towards the object surface, the middle cemented surface bulges towards the image surface, and the other side close to the image surface bulges towards the object surface, both sides of the fourth lens L4 bulge towards the object surface, and the fifth lens is a cover glass, and both sides of the cover glass are flat.

[0089] The radius of curvature of one side of the first lens L1 close to the object surface is r11, the radius of curvature of the other side close to the image surface is r12, the radius of curvature of one side of the second lens L2 close to the object surface is r21, the radius of curvature of the other side close to the image surface is r22, the focal length of the first lens L1 is f1, and the focal length of the second lens L2 is f2, satisfying:

[0090] The clear aperture radius of the surface of the third lens L3 close to the object surface is R31, the clear aperture radius of the cemented surface in the middle is R32, and the clear aperture radius of the surface of the third lens L3 close to the image surface is R33. The central thickness of the third lens L3 is t3. The clear aperture radius of the surface of the fourth lens L4 close to the object surface is R41, and the clear aperture radius of the surface of the fourth lens L4 close to the image surface is R42. The central thickness of the fourth lens L4 is t4, and they satisfy:

[0091] The radius of curvature of the surface of the first lens L1 close to the object surface is -8.016 mm, and the clear aperture radius is 4.62 mm. The radius of curvature of the surface of the first lens L1 close to the image surface is -14.077 mm, and the clear aperture radius is 7.61 mm. The material of the first lens L1 is H-ZLAF92, and the central thickness is 10.359 mm. The central thickness between the adjacent surfaces of the first lens L1 and the second lens L2 is 5.000 mm.

[0092] The radius of curvature of the surface of the second lens L2 close to the object surface is 142.037 mm, and the clear aperture radius is 7.63 mm. The radius of curvature of the surface of the second lens L2 close to the image surface is -44.713 mm, and the clear aperture radius is 7.58 mm. The material of the second lens L2 is H-ZLAF68C, and the central thickness is 2.947 mm. The central thickness between the adjacent surfaces of the second lens L2 and the third lens L3 is 2.000 mm.

[0093] The radius of curvature of the surface of the third lens L3 close to the object surface is 14.792 mm, and the clear aperture radius is 6.98 mm. The radius of curvature of the middle cemented surface is -21.763 mm, and the clear aperture radius is 5.17 mm. The radius of curvature of the surface of the third lens L3 close to the image surface is 20.295 mm, and the clear aperture radius is 4.62 mm. The third lens L3 is composed of two lenses cemented together. The material of the lens close to the object surface is H-ZPK5, and the central thickness is 8.852 mm. The material of the lens close to the image surface is H-ZF88, and the central thickness is 2.000 mm. The central thickness between the adjacent surfaces of the third lens L3 and the fourth lens L4 is 5.536 mm.

[0094] The radius of curvature of the surface of the fourth lens L4 close to the object surface is 7.176 mm, and the clear aperture radius is 3.92 mm. The radius of curvature of the surface of the fourth lens L4 close to the image surface is 20.972 mm, and the clear aperture radius is 2.88 mm. The material of the fourth lens L4 is H-ZLAF68C, and the central thickness is 3.922 mm. The central thickness between the adjacent surfaces of the fourth lens L4 and the fifth lens L5 is 4.216 mm.

[0095] The fifth lens L5 is a standard #1.5 cover glass with a refractive index of 1.52, made of H-K8, and has a central thickness of 0.170 mm. The clear aperture radius of the side of the fifth lens L5 close to the object surface is 0.56 mm, and the clear aperture radius of the side close to the image surface is 0.50 mm.

[0096] The focal lengths f1 of the first lens L1, f2 of the second lens L2, f3 of the third lens L3, and f4 of the fourth lens L4 are respectively: -133.14 mm, 38.37 mm, -113.97 mm, 10.77 mm. The overall optical length TTL of the entire objective lens is 45 mm.

[0097] r11 = -8.016 mm, r12 = -14.077 mm, r21 = 142.037 mm, r22 = -44.713 mm, f1 = -133.14 mm, f2 = 38.37 mm, R31 = 6.98 mm, R32 = 5.17 mm, R33 = 4.62 mm, t3 = 8.852 mm + 2.000 mm = 10.852 mm, R41 = 3.92 mm, R42 = 2.88 mm, t4 = 3.922 mm,

[0098]

[0099] Figure 13 The chief ray angles of different fields of view are shown. It can be seen from the figure that the chief ray angles within the entire field of view are all less than 0.1°, indicating good telecentric characteristics. In this way, the chief rays of different fields of view are not only almost parallel to the axes of the respective cores, but also have almost the same fiber incident cone angle, which can maximize the coupling efficiency between the coupling objective lens and the imaging fiber bundle.

[0100] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-mode endoscope catheter, characterized in that, The endoscope catheter includes an imaging fiber bundle, an imaging lens group focused on one end face of the imaging fiber bundle, and a protective sleeve sleeved on the periphery of the imaging fiber bundle. The imaging fiber bundle includes a confocal fiber and a wide-field imaging catheter. The wide-field imaging catheter includes a wide-field illumination fiber and a wide-field imaging fiber arranged coaxially. One end of the protective sleeve is connected with an end cap. The imaging lens group is located inside the end cap. The imaging lens group includes a wide-field imaging group and a confocal imaging group. The working distance of the wide-field imaging group is in the order of millimeters, and the working distance of the confocal imaging group is in the order of micrometers.

2. The endoscopic catheter according to claim 1, wherein The cross-section of the end cap is elliptical. The confocal fiber and the wide-field imaging catheter are arranged side by side, or the confocal fiber and the wide-field imaging catheter are arranged coaxially, and the confocal fiber is located inside the wide-field imaging catheter.

3. The endoscope catheter according to claim 2, wherein, Each lens in the imaging lens group includes a wide-field imaging area and a confocal imaging area. The wide-field imaging areas of all lenses form the wide-field imaging group, and the confocal imaging areas of all lenses form the confocal imaging group. The central thickness of the wide-field imaging area and the confocal imaging area of a single lens is not equal.

4. A dual-mode endoscopic imaging system, characterized in that, The imaging system includes a wide-field imaging mode and a confocal imaging mode, including Light source module: including a confocal imaging light source, a wide-field imaging light source, a first beam combiner, and an expander lens group. The confocal imaging light source and the wide-field imaging light source are respectively located on two incident light paths of the first beam combiner, and the expander lens group is located on the outgoing light path of the first beam combiner; Scanning module: sequentially including a two-dimensional scanning device, a coupling objective lens, and the endoscope catheter as described in claim 3. The two-dimensional scanning device is used to deflect the confocal imaging light. The coupling objective lens is used to couple the imaging signal into the endoscope catheter. The endoscope catheter is used to focus the confocal imaging light source or the wide-field imaging light source on the target position to excite a confocal signal light or a wide-field signal light. The two-dimensional scanning device is located on the outgoing light path of the expander lens group. A relay lens group and a scatter plate that can cut into / cut out the light path are sequentially arranged between the two-dimensional scanning device and the coupling objective lens; Confocal detection module: including a dichroic mirror for separating the confocal signal light and a first detection component for collecting the confocal signal light. The dichroic mirror is located between the expander lens group and the two-dimensional scanning device, the expander lens group is located on the incident light path of the dichroic mirror, the two-dimensional scanning device is located on the outgoing light path of the dichroic mirror, and the first detection component is located on the transmitted light path of the dichroic mirror; Wide-field detection module: including a polarization filter for separating the wide-field signal light and a second detection component for collecting the wide-field signal light. The polarization filter cuts into / cuts out the light path synchronously with the scatter plate. When the polarization filter cuts into the light path, the relay lens group is located on the incident light path of the polarization filter, the scatter plate is located on the transmitted light path of the polarization filter, and the second detection component is located on the reflected light path of the polarization filter.

5. A dual-mode endoscopic imaging system according to claim 4, wherein, The specific usage method of the wide-field imaging mode is as follows: The polarization filter and the diffuser are inserted into the optical path. The confocal imaging light source is turned off. The wide-field imaging light source emits the illumination light required for wide-field imaging. After passing through the first beam combiner, it is expanded by the beam expander group. The expanded beam is reflected by the dichroic mirror and enters the two-dimensional scanning device in a stationary state. Then it is reflected to the relay lens group. After that, it passes through the polarization filter and the diffuser in sequence and enters the coupling objective lens, and is coupled into the imaging optical fiber bundle of the endoscope catheter. Then it is focused on the object side through the wide-field imaging area of the imaging lens group in the end cap, and the target is imaged in the wide-field imaging mode. The generated wide-field signal light returns along the original optical path to the polarization filter, and is detected and imaged by the second detection component after being reflected by the polarization filter.

6. A dual-mode endoscopic imaging system according to claim 4, wherein, The specific usage method of the confocal imaging mode is as follows: The polarization filter and the diffuser are removed from the optical path. The wide-field imaging light source is turned off. The confocal imaging light source emits the excitation light required for confocal imaging. After passing through the first beam combiner, it is expanded by the beam expander group. The expanded beam is reflected by the dichroic mirror and enters the two-dimensional scanning device in a deflected and scanned state, so as to be deflected into the relay lens group. After that, the beams deflected at various angles enter the coupling objective lens, and are coupled into the imaging optical fiber bundle of the endoscope catheter. Then it is focused on the object side through the confocal imaging area of the imaging lens group in the end cap, and the target is imaged in the confocal mode, exciting the confocal signal light. The confocal signal light returns along the original optical path to the dichroic mirror, and is detected and imaged by the first detection component after passing through the dichroic mirror.

7. The imaging system according to claim 4, wherein The coupling objective lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the two-dimensional scanning device to the endoscope catheter direction, and the third lens is a doublet lens.

8. The imaging system according to claim 7, wherein One side of the coupled objective lens facing the two-dimensional scanning device is the object surface, and the side facing the endoscope catheter is the image surface. The clear aperture radius of the side of the first lens close to the image surface is R12. The clear aperture radius of the side of the second lens close to the object surface is R21, and the clear aperture radius of the side of the second lens close to the image surface is R22. The clear aperture radius of the side of the third lens close to the object surface is R31, and the clear aperture radius of the side of the third lens close to the image surface is R33. The clear aperture radius of the side of the fourth lens close to the object surface is R41, and the clear aperture radius of the side of the fourth lens close to the image surface is R42.

9. The imaging system according to claim 7, wherein One side of the coupled objective lens facing the scattering sheet is the object surface, and the side facing the endoscope catheter is the image surface. The radius of curvature of the side of the first lens close to the object surface is r11, and the radius of curvature of the side close to the image surface is r12. The radius of curvature of the side of the second lens close to the object surface is r21, and the radius of curvature of the side close to the image surface is r22. The focal length of the first lens is f1, and the focal length of the second lens is f2, satisfying:

10. The imaging system according to claim 8 or 9, characterized in that, The focal length of the coupling objective lens is 9 mm, the parfocal distance is 45 mm, and the maximum semi-aperture is 8 mm.

Images